Philips TDA1072A Datasheet

INTEGRATED CIRCUITS

DATA SH EET

TDA1072A

AM receiver circuit

Product speciﬁcation File under Integrated Circuits, IC01

May 1984

Philips Semiconductors Product speciﬁcation

AM receiver circuit TDA1072A

GENERAL DESCRIPTION

The TDA1072A integrated AM receiver circuit performs the active and part of the filtering functions of an AM radio receiver. It is intended for use in mains-fed home receivers and car radios. The circuit can be used for oscillator frequencies up to 50 MHz and can handle r.f. signals up to 500 mV. R.F. radiation and sensitivity to interference are minimized by an almost symmetrical design. The voltage-controlled oscillator provides signals with extremely low distortion and high spectral purity over the whole frequency range even when tuning with variable capacitance diodes. If required, band switching diodes can easily be applied. Selectivity is obtained using a block filter before the i.f. amplifier.

Features

• Inputs protected against damage by static discharge

• Gain-controlled r.f. stage

• Double balanced mixer

• Separately buffered, voltage-controlled and temperature-compensated oscillator, designed for simple coils

• Gain-controlled i.f. stage with wide a.g.c. range

• Full-wave, balanced envelope detector

• Internal generation of a.g.c. voltage with possibility of second-order filtering

• Buffered field strength indicator driver with short-circuit protection

• A.F. preamplifier with possibilities for simple a.f. filtering

• Electronic standby switch.

QUICK REFERENCE DATA

Supply voltage range V Supply current range I R.F. input voltage for S + N/N = 6 dB at m = 30% V R.F. input voltage for 3% total harmonic

distortion (THD) at m = 80% V

A.F. output voltage with V

= 1 MHz; m = 30% and fm= 400 Hz V

A.G.C. range: change of V

= 2 mV;

for 1 dB change of V

o(af)

Field strength indicator voltage at

= 500 mV; R

= 2,7 kΩ V

L(9)

PACKAGE OUTLINE

16-lead DIL; plastic (SOT38); SOT38-1; 1996 August 09.

o(af)

IND

7,5 to 18 V

15 to 30 mA

typ. 1,5 µV

typ. 500 mV

typ. 310 mV typ. 86 dB

typ. 2,8 V

May 1984 2

Philips Semiconductors Product speciﬁcation

AM receiver circuit TDA1072A

(1) Coil data: TOKO sample no. 7XNS-A7523DY; L1 : N1/N2 = 12/32; Qo = 65; QB = 57.

Filter data: Z

= 700 Ω at R

= 3 kΩ; ZI = 4,8 kΩ.

3-4

Fig.1 Block diagram and test circuit (connections shown in broken lines are not part of the test circuit).

May 1984 3

Philips Semiconductors Product speciﬁcation

AM receiver circuit TDA1072A

FUNCTIONAL DESCRIPTION Gain-controlled r.f. stage and mixer

The differential amplifier in the r.f. stage employs an a.g.c. negative feedback network to provide a wide dynamic range. Very good cross-modulation behaviour is achieved by a.g.c. delays at the various signal stages. Large signals are handled with low distortion and the S/N ratio of small signals is improved. Low noise working is achieved in the differential amplifier by using transistors with low base resistance.

A double balanced mixer provides the i.f. output signal to pin 1.

Oscillator

The differential amplifier oscillator is temperature compensated and is suitable for simple coil connection. The oscillator is voltage-controlled and has little distortion or spurious radiation. It is specially suitable for electronic tuning using variable capacitance diodes. Band switching diodes can easily be applied using the stabilized voltage V buffered oscillator output (pin 10) is available for driving a synthesizer. If this is not needed, resistor R

L(10)

Gain-controlled i.f. ampliﬁer

This amplifier comprises two cascaded, variable-gain differential amplifier stages coupled by a band-pass filter. Both stages are gain-controlled by the a.g.c. negative feedback network.

. An extra

11-16

can be omitted.

Detector

The full-wave, balanced envelope detector has very low distortion over a wide dynamic range. Residual i.f. carrier is blocked from the signal path by an internal low-pass filter.

A.F. preampliﬁer

This stage preamplifies the audio frequency output signal. The amplifier output has an emitter follower with a series resistor which, together with an external capacitor, yields the required low-pass for a.f. filtering.

A.G.C. ampliﬁer

The a.g.c. amplifier provides a control voltage which is proportional to the carrier amplitude. Second-order filtering of the a.g.c. voltage achieves signals with very little distortion, even at low audio frequencies. This method of filtering also gives fast a.g.c. settling time which is advantageous for electronic search tuning. The a.g.c. settling time can be further reduced by using capacitors of smaller value in the external filter (C16 and C17). The a.g.c. voltage is fed to the r.f. and i.f. stages via suitable a.g.c. delays. The capacitor at pin 7 can be omitted for low-cost applications.

Field strength indicator output

A buffered voltage source provides a high-level field strength output signal which has good linearity for logarithmic input signals over the whole dynamic range. If the field strength information is not needed, R

can be omitted.

L(9)

Standby switch

This switch is primarily intended for AM/FM band switching. During standby mode the oscillator, mixer and a.f. preamplifier are switched off.

Short-circuit protection

All pins have short-circuit protection to ground.

May 1984 4

Philips Semiconductors Product speciﬁcation

AM receiver circuit TDA1072A

RATINGS

Limiting values in accordance with the Absolute Maximum Rating System (IEC 134) Supply voltage V

Total power dissipation P Input voltage V

Input current I Operating ambient temperature range T Storage temperature range T Junction temperature T

THERMAL RESISTANCE

= V

13-16

tot

 max. 12 V

14-15

, −V

−V

14-16

, I15 max. 200 mA

14 amb stg j

, V

15-16

max. 20 V max. 875 mW

max. 0,6 V max. VPV

−40 to + 80 °C

−55 to + 150 °C

max. + 125 °C

From junction to ambient R

th j-a

= 80 K/W

DEVICE CHARACTERISTICS

= V

13-16

= 8,5 V; T

= 25 °C; fi = 1 MHz; fm = 400 Hz; m = 30%; fif = 460 kHz; measured in test circuit of Fig.1;

amb

unless otherwise speciﬁed

PARAMETER SYMBOL MIN. TYP. MAX. UNIT

Supplies

Supply voltage V Supply current I

= V

13-16

= I

7,5 8,5 18 V

15 23 30 mA

R.F. stage and mixer

Input voltage (d.c. value) V R.F. input impedance at V

R.F. input impedance at V

< 300 µVR

> 10 mV R

I.F. output impedance R

, V

14-16

, R

14-16

, C

14-16

, R

14-16

, C

14-16 1-16

1-16

15-16

15-16 15-16 15-16 15-16

− VP/2 − V

− 5,5 − kΩ

− 25 − pF

− 8 − kΩ

− 22 − pF

500 −−kΩ

− 6 − pF

Conversion transconductance

before start of a.g.c. I

1/Vi

− 6,5 − mA/V

Maximum i.f. output voltage, inductive

coupling to pin 1 V

1-13(p-p)

− 5 − V

D.C. value of output current (pin 1)

= 0 V I

at V

− 1,2 − mA A.G.C. range of input stage − 30 − dB R.F. signal handling capability:

input voltage for THD = 3% at m = 80% V

i(rms)

− 500 − mV

May 1984 5

Philips Semiconductors Product speciﬁcation

AM receiver circuit TDA1072A

PARAMETER SYMBOL MIN. TYP. MAX. UNIT

Oscillator

Frequency range f

osc

Oscillator amplitude (pins 11 to 12) V External load impedance R External load impedance for no oscillation R Ripple rejection at V

= 100 Hz

(RR = 20 log [V

13-16/V11-16

Source voltage for switching diodes (6 × V

P(rms)

= 100 mV;

]) RR − 55 − dB

D.C. output current (for switching diodes) −I Change of output voltage at

∆I11= 20 mA (switch to maximum load) ∆V

Buffered oscillator output

D.C. output voltage V Output signal amplitude V Output impedance R Output current −I

I.F., a.g.c. and a.f. stages

D.C. input voltage V I.F. input impedance R

I.F. input voltage for

THD = 3% at m = 80% V Voltage gain before start of a.g.c. V A.G.C. range of i.f. stages: change of

for 1 dB change of V

3-4

= 75 mV ∆V

3-4(ref)

A.F. output voltage at V A.F. output voltage at V

3-4(if) 3-4(if)

;

o(af)

= 50 µVV = 1 mV V

A.F. output impedance (pin 6) Z

Indicator driver

Output voltage at V

= 2,7 kΩ V

L(9)

Output voltage at V

= 2,7 kΩ V

L(9)

= 0 mV;

= 500 mV;

Load resistance R

11-12

12-11(ext) 12-11(ext)

11-16

10-16 10-16(p-p)

10(peak)

, V

3-16

4-16 3-4 3-4

3-4 3-4/V6-16

3-4 o(af) o(af)

−3,5 − kΩ

9-16

L(9)

0,6 − 60 MHz

− 130 150 mV

0,5 − 200 kΩ

−−60 Ω

− 4,2 − V 0 − 20 mA

− 0,5 − V

− 0,7 − V

− 320 − mV

− 170 −Ω

−−3mA

− 2,0 − V

2,4 3 3,9 kΩ

− 7 − pF

− 90 − mV

− 68 − dB

− 55 − dB

− 130 − mV

− 310 − mV

− 20 150 mV

2,5 2,8 3,1 V 1,5 −−kΩ

May 1984 6

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